著者

Calvino Martin Kamada Hiroshi Mizoguchi Tsuyoshi

出版者

Japanese Society for Plant Cell and Molecular Biology

雑誌

Plant biotechnology (ISSN:13424580)

巻号頁・発行日

vol.22, no.3, pp.179-183, 2005-09-01

参考文献数

42

被引用文献数

9 4

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Plants in the genus <i>Arabidopsis</i> are facultative LD plants that flower much earlier under LD conditions than SD regimens, with the photoperiod (or LD) pathway contributing to floral acceleration. <i>LHY</i> and <i>CCA1</i> genes, among other factors, have central roles in the circadian clock of <i>Arabidopsis</i>, which plays a key role in measuring day length. <i>GI</i> gene mediates the circadian clock and floral activator genes, <i>CO</i> and <i>FT</i>, to control photoperiodic flowering. <i>GI</i> is required to set the peak phase of <i>CO</i> expression at the end of the light period under LD conditions, so that the <i>CO</i> protein is stabilized and activated by light to increase <i>FT</i> expression. However, recent studies have demonstrated that the role of SDs is not solely to switch off CO activity. For example, GI interacts with SPY, a negative regulator of the GA signal. The flowering times of <i>gi</i> mutants were still significantly later under SD conditions than LD regimes, which suggests that <i>GI</i> has a potential role in accelerating the start of flowering, even under SDs. Over-expression of either <i>FT</i> or <i>TSF</i> genes caused early flowering, and the acceleration of flowering was enhanced under SDs, suggesting that SDs have an additional role to that in the <i>LHY</i>/<i>CCA1</i>-<i>GI</i>-<i>CO</i>-<i>FT</i> pathway. In this short review, we discuss the hidden roles of SDs in controlling flowering based on recent studies of the molecular genetics of flowering time in <i>Arabidopsis</i>.